When you go to check for this update in Windows Update you will also notice a Windows 10 November Update being available. This is another update for the Windows 10 OS itself and adds more improvements and new features. For more information on this update, check Windows 10 November update: FAQ.

This was necessitated by major reliability issues, in particular with Surface Book, related to power management, Windows Hello, and the display driver. I’ve certainly experienced these issues myself, and as I’m traveling with Surface Book this week, I’m obviously keen to see the issues cleaned up.

Anyway … Last night Microsoft pushed the firmware updates out via Windows Update (along with an unrelated Windows 10 cumulative update for everyone on the new OS). I’ve installed it on my Surface Book, but it’s too early to know whether this has fixed the issues I’ve seen. But, again, the big question here is what changed.

Update: Here’s the list of updates in this latest firmware, update, which will be identified as System Firmware Update – 11/18/2015 in Windows Update. (These updates are identical across Surface Pro 4 and Surface Book.)